Generally, wireless enabled devices have to pass a variety of industry and regulatory certifications before they can be put on the market. The certifications include regulatory/compliance testing such as EMC (Electro Magnetic Compatibility), conformance testing such as protocol, Radio Frequency (RF), Radio Resource Management (RRM) and Location Based Services (LBS), as well as performance testing such as over the air (OTA) measurements. Up to the 4th generation of mobile communication, commonly known as Long Term Evolution (LTE), conformance measurements including receiver performance assessment, are based on conducted measurements, assuming the availability of appropriate connectors. Only a very few measurements, such as the Total Radiated Power (TRP) and the Total Isotropic Sensitivity (TIS), are additionally specified for OTA measurement environments.
When looking towards the next generation of mobile communications (e.g., the 5th generation) the need for OTA testing increases, since frequencies far beyond the spectrum that has been used so far for mobile communications are being considered by the standardization body 3GPP. Basically no frequency up to 100 GHz shall be precluded, in particular operating frequencies in the 28 GHz range are of significant interest.
Such high operating frequencies require high gain antenna implementations to overcome the increased free space path loss, and consequently antenna array deployments rather than single antenna elements will be seen in the new generation of mobile devices. Performing conducted measurements with several antennas is not practical and therefore more and more measurements have to be performed over the air. Since more and more different antenna array deployments for different devices under test (DUTs) are seen, a measurement setup and method is desired for conducting OTA performance testing for a variety of DUTs having different antenna array deployments and properties.
The document “Test Plan for Wireless Device over-the-Air performance,” Version 3.7, by the Cellular Telecommunications Industry Association (CTIA)—The Wireless Association, issued in June 2017 on www.ctia.org/certification, relates to testing of wireless devices and defines test requirements for performing radiated radio frequency (RF) power and receiver performance measurements on wireless devices. This document is incorporated herein by reference. Section 5 of the document describes several test procedures for the radiated power measurement of a DUT. Section 6 of the document is related to several test procedures for measuring the receiver performance of a DUT. The test procedures consider different mobile radio standards, such as Universal Mobile Telecommunications System (UMTS), Global System for Mobile Communications (GSM) and Long Term Evolution (LTE).
Further, the test procedures contain requirements regarding requirements for performing spherical scans for transceiver testing. The document additionally specifies the sequence of measurement points for transmitter testing and receiver testing. Appendix A and figures A27 to A33 of the cited document disclose different test setups for transceiver performance measurements of a DUT. The cited document, however, does not consider the 5th generation of mobile radio standards, which requires improved measurement procedures to take into account the higher frequencies used with the 5th generation of mobile radio standards and the more complex and diverse antenna array deployments.
Accordingly, there is a need for a test system and a method for improving the measurement process of DUTs, such as mobile devices designed for use with the 5th generation of mobile standards. The test system should be able to perform testing on different DUTs (e.g., mobile phones) without any knowledge about specific device configurations, such as antenna array implementation. In other words, the test system should be capable of performing a “black box” testing for a variety of different DUTs with different antenna array implementations.